The known technology in the field of the invention has been disclosed in publications EP 0297843, EP 0447183, U.S. Pat. No. 6,266,944, US 2004/0016210, US 2003/0222127 and EP 1693185.
The first three publications describe methods and apparatuses for producing sealed envelopes, wherein the envelope and the inserted letters are produced separately and from different source webs and then folded in a suitable manner and sealed mechanically inside the envelopes.
The fourth publication describes a method for cutting, folding and gluing identical envelopes from a paper web.
The fifth publication describes a method which is the closest to the invention, wherein an envelope form and the letters, coupons and the like to be inserted in the envelope are printed on the same paper web.
The problem with the publication representing the closest prior art is that a specific field has been assigned for the printouts in the paper web in such manner that the envelope form and the letter forms should cover at least half of that field. Consequently, in printing individual mail pieces which vary in size, the size of the field must be adapted to the space required by the largest possible mail piece. Therefore, in almost each mail piece, a considerable portion of the paper web must be cut off to be recycled, or if one wishes to avoid wasting paper, one can only produce one-size mail pieces which must also be so designed that the field assigned for a single printout becomes completely filled. However, such economy measures restrict the efficient use of the method to a considerable degree, so the average paper waste of 20-30% must only be accepted.
The sixth publication describes a method in which mail pieces of different sizes are made from the same paper web by cutting different-size envelopes of the web according to need. The greatest problems with this application are the complexity of the method, many oblique cuts in different directions and turns of the envelopes and the letters, many flaps and their gluing and folding, etc. This makes the entire method slow and susceptible to malfunctions and not suitable for efficient processing of large mass deliveries.